Novel process for preparing a haloether

ABSTRACT

The haloether, 3-halo-3-methylbutyl methyl ether, of the formula CAN BE PREPARED WHEN METHYLAL IS REACTED WITH ISOBUTYLENE IN THE PRESENCE OF BX3, wherein X is chloro, bromo or iodo. This haloether can be converted to isoprene by known pyrolysis methods.

United States Patent Turner [451 Oct. 10,1972

[ NOVEL PROCESS FOR PREPARING A HALOETHER [72] Inventor: John O. Turner, West Chester, Pa.

[73] Assignee: Sun Oil Company, Philadelphia, Pa.

[22] Filed: March 22, 1971 [21] Appl. No.: 127,042

OTHER PUBLICATIONS Dermer et al., J. Amer. Chem. Soc. 74, 4565- 4 597 (l952) Primary Examiner-Howard T. Mars Attorney-George L. Church, Donald R. Johnson, Wilmer E. McCorquodaJe and Stanford M. Back [57] ABSTRACT The haloether, 3-halo-3-methylbutyl methyl ether, of the formula (I'JHa CH5|CCH2OH2OCH3 can be prepared when methylal is reacted with isobutylene in the presence of BX wherein X is chloro,

bromo or iodo. This haloether can be converted to isoprene by known pyrolysis methods.

4 Claims, No Drawings NOVEL PROCESS FOR PREPARING A I-IALOETHER CROSS-REFERENCE TO RELATED APPLICATION The subject matter of this case is related to'the subject matter of co-pending application, Ser. No. 126,934 filed Mar. 22, 1971, in the name of John O. Turner and entitled NOVEL PROCESS FOR THE PREPARA- TION OF ISOPRENE.

BACKGROUND OF THE INVENTION This invention relates to a novel process for the preparation of the haloether 3-halo-3-methylbutyl methyl ether by the reaction of methylal and isobutylene with BCl BBr or B1 The resulting haloether is useful as an intermediate in the preparation of isoprene, as taught by U.S. Pat. No. 3,360,583, wherein the chloroether is pyrolyzed to give isoprene, methanol, methyl chloride and HG].

In related application, Ser. No. 126,934, of John O. Turner, referred to above, there is taught the reaction of methylal with isobutylene in the presence of BF to produce a mixture of 1,3-dimethoxy-3-methylbutane, 4-methoxy-2-methylbutene-l and isoprene, which mixture, on pyrolysis, yields isoprene and methanol.

SUMMARY OF THE INVENTION It has now been found that a useful intermediate in the synthesis of isoprene may be formed in accordance with the following reaction scheme:

3-Ha10-3-Methylbutyl Methyl Ether I wherein X is chlorine, bromine or iodine. Minor amounts of the corresponding t-butyl halide are likewise produced by this process in amounts of percent or less.

The results of this process are quite surprising in view of the above-reported results with BF; wherein a mixture of entirely different reaction products is reported.

DESCRIPTION OF THE INVENTION desirably the reactants should be used in molar ratios of 3:3:1 of methylal, isobutene and 8X respectively.

The resulting haloether product is readily recovered by treating the reaction solution with an alkaline reagent such as aqueous sodium or potassium carbonate to form an aqueous phase containing the boron residue and an organic phase containing the haloether and a minor amount of the t-butyl halide.

his invention WlII now be illustrated by the following examples.

EXAMPLE 1 To a pressure vessel containing 228 grams (3.0 m) of methylal, l 17 grams 1.0 m) of BCI;, is added 56 grams (1.0 m) of isobutylene. The mixture is stirred at room temperature for 2 hours, at the end of which time the product mixture is neutralized with aqueous Na CO and the resulting organic phase, containing of 123 grams percent yield) of 3-chloro-3-methylbutyl methyl ether, is recovered.

EXAMPLE 2 In accordance with the procedures of Example 1, but substituting 250.6 grams (1.0 m) of BBr for the BCl and adding 456 grams (6.0 m) of methylal, there is obtained 3-bromo-3-methylbutyl methyl ether percent yield).

EXAMPLE 3 In accordance with the procedures of Example 1, but substituting 196 grams (0.5 m) of 81;, for the BCI;,, and 56 grams (1.0 m) of isobutylene, there is obtained 3- iodo-3-methylbutyl methyl ether (80 percent yield).

What is claimed is:

1. A process for the production of a haloether of the formula 

2. The process according to claim 1 wherein BCl3 is employed and the product is 3-chloro-3-methylbutyl methyl ether.
 3. The process according to claim 1 wherein BBr3 is employed and the product is 3-bromo-3-methylbutyl methyl ether.
 4. The process according to claim 1 wherein BI3 is employed and the product is 3-iodo-3-methylbutyl methyl ether. 